GRAPTOLITES OF NEW YORK, PART 2 367 



Diplograptus angustifolius Nicholson. Geol. Soc. Quar. Jour. 1868. p. 525, 



pi. 19, fig. S.i) 

 Diplograptus angustif olius Lapworth. Cat. West. Scott. Foss. 1876. pi. 2, 



tig- 35 

 Diplograptus angustif olius Lapworth. Belfast Nat. Field Club. Rep't & 



Proc. Apx. 1877. v. 1, pt 4, p. 132, pi. 6, fig. 11 

 Diplograptus angustif olius Lapworth. Ann. & Mag. Nat. Hist. Ser. 5. 



1880. 5:21 

 Diplograptus angustifolius Walcott. Alb. Inst. Trans. v. 10. 1 88 1 . 



(Advance sheets, 1879. p. 34) 

 Diplograptus angustifolius Lapworth. Geol. Sur. Can. Rep't. Ser. 2. 1886. 



2 : 22D 

 Diplograptus angustifolius Lapworth. Science. 1887. 9:320 

 Diplograptus angustifolius ? Ami. Geol. Sur. Can. Rep't. Ser. 2. 1889. 



v. 3, pt 2, p.n6K 

 Diplograptus angustifolius Walcott. Geol. Soc. Am. Bui. 1890. 1:339 

 Diplograptus angustifolius Barrois. Ann. Soc. Geol. du Nord. 1892. 20:145 

 Diplograptus angustifolius Gurley. Jour. Geol. 1896. 4:298 

 Diplograptus angustifolius Ruedemann. N. Y. State Mus. Bui. 42. 1901. 



p.54iff 

 Diplograptus angustifolius Fearnsides. Section C, Belfast. 1902. Separates, 



p. 1 

 Diplograptus angustifolius Weller. Geol. Sur. N. J. Pal. 1902. 3:52 

 Diplograptus cf. angustifolius Dale. U. S. Geol. Sur. Bui. 242. 1904. p. 33 



Description. Synrhabdosome not observed. Rhabdosomes small 

 (maximum length observed 27 mm), of uniform width, the full width being 

 attained within 5 mm and amounting to 1.2 to 1.5 mm. Sicula not observed, 

 sicular end furnished with a short virgella and two lateral spines, which are 

 so thin that they are observed with difficulty. Nemacaulus also very deli- 

 cate and hairlike, though obtaining a length equal to that of the rhabclo- 

 some. Thecae closely arranged, numbering 11 to 14 in 10 mm (28-34 to 

 the inch), inclined at 30 , overlapping not quite one third of their length, 

 the free ventral margin curved, concave below and very convex above. 

 The apertural margin horizontal, in flattened specimens mostly more or 

 less convex. 



